I've applied to Railcorp already. Kinda fucked for Accenture for an internship (as amazing as that would be) because my average is probably a credit, if that, though this semester's looking like the one where I turn it around and get straight 80s.
EDIT: What's the pay like at Railcorp, if you don't mind me asking?
2nd year: about $16 an hour
3rd year : about $18 an hour
4th+ year: about $21 an hour
Everyone at railcorp is getting a payrise in a couple of weeks, so maybe add 4% to that. They put you on a casual contract so you only work the hours you turn up for (although most managers want you to have regular rostered hours).
The pay is a bit less than other places (GHD's interns are on the grad salary, so around $28 an hour), but hey, free transport kinda balaces it out.
I reckon you could do an accenture internship with a credit average (and plus since you seem to do alot of extra-curric stuff) and since you're in 4th year now yeah? Couldn't hurt to try anyway.